Hello Studley,
Sounds like a frustrating issue. Input transformers can resonate 10 dB (or so) at around 40 kHz to 80 kHz. This may cause instability issues or perhaps input overload with a leaky DAC. At the least, resonance can give you a couple dB's of lift at 20 kHz. That lift might sound irritating...
You can properly damp the resonance with an RC Zobel using component values recommended by the manufacturer.
For reference, see pages 370 and 371 of DS's "Small Signal Audio Design" for his discussion of circuits and FR graphs of this issue. He shows a Zobel of 3K3 ohm in series with 4n3 across the output of a Sowter 3276.
Jensen Transformers, accompanied by their recommended compensation circuits, also work well IME.
Apologies, if you have performed this compensation already.
HTH,
David
Sounds like a frustrating issue. Input transformers can resonate 10 dB (or so) at around 40 kHz to 80 kHz. This may cause instability issues or perhaps input overload with a leaky DAC. At the least, resonance can give you a couple dB's of lift at 20 kHz. That lift might sound irritating...
You can properly damp the resonance with an RC Zobel using component values recommended by the manufacturer.
For reference, see pages 370 and 371 of DS's "Small Signal Audio Design" for his discussion of circuits and FR graphs of this issue. He shows a Zobel of 3K3 ohm in series with 4n3 across the output of a Sowter 3276.
Jensen Transformers, accompanied by their recommended compensation circuits, also work well IME.
Apologies, if you have performed this compensation already.
HTH,
David
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Have you tried just using a RCA-to-XLR cable (wired according to the hypex data sheet) without the transformer?
Is the NC400 module stereo or single channel? I cannot find this info on their product spec page.
Question: Is the new NCore technology proprietary to Hypex, or is this a new Class D industry designation available to other vendors? I'm particularly interested in how this (NCore) technology compares to the B&O ICEPower Class D amp modules.
The nCore technology is proprietary to Hypex (similar to how ICEpower is to B&O), but there are two versions of the modules, one exclusively aimed for DIY community and one aimed for commercial markets and brands (similar to how ICEpower modules are).
Just get 2x NC400 and one SMPS600 to start then add the second SMPS600 when funds allow. 🙂
There are major differences....
Hypex Ncore is available for DIY. No ICEpower modules are available for DIY (although there are a few rougue modules out there ...)
Most ICEpower modules are self-powered, with a build-in SMPS. Hypex don't have such solutions.
Measurement-wise, there are big differences.... not in favour of ICEpower to say the least.
Sonically... Ncore is way beyond any ICEpower module. I know, I've tried all of them.
The NC400 is within reach ($), just can't become an active project right now. I've got another Class D project underway. A few years ago I took the ICEPower amp plunge for my home theater and have never looked back. I thought the sound they produced was nothing short of phenomenal. At least the best I'd ever heard or been able to afford up until then. Now with some time on hands, I've been playing with some DIY amps. My first was a 100wpc Class AB. And now a non-nCore Class D amp. With nothing really 'high-end' in my audio chain, I may never realize the true potential of a Class D amp of any stripe, or any other class amp for that matter. But it's all fun building them and trying to discern the subtleties in the sonic characteristics.
Sorry for getting a little OT.
Well then... I may have to have a second look! You make them sound like the holy grail of audio amps. And they may well be. Are there commercial products out there that use Hypex's nCore technology? I guess my ears are just getting old. 😀
Mogami, Gotham et al all seem to use polyethylene insulation. Anybody know a reasonably priced cable that has PTFE insulation?
I wouldn't worry about this part. Polyethylene is a better choice than PTFE unless the PTFE is wrapped, which prevents excessive conductor re-heating during extrusion. PE doesn't need the high heat as it's more like a wax, and flows more easily.
Wrapped is only used by specialty audio cables, for the most part. I'd be happy with polyethylene, be glad it's not PVC.
Make your own.....Get some bare occ wire and some eptfe tubing....Through a shield around it if you need it...state of the art for pennies on the dollar compared to commercial cables.
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